Auto merge of #85421 - Smittyvb:rm_pushpop_unsafe, r=matthewjasper

[rust.git] / clippy_lints / src / map_unit_fn.rs

diff --git a/clippy_lints/src/map_unit_fn.rs b/clippy_lints/src/map_unit_fn.rs
index 1f9ae8c931a1ee3aea3cbb5e683987a31ce71252..57cd907e77e8da975a56773a5e357e0125de3394 100644 (file)
--- a/clippy_lints/src/map_unit_fn.rs
+++ b/clippy_lints/src/map_unit_fn.rs
@@ -1,4 +1,7 @@
-use crate::utils::{is_type_diagnostic_item, iter_input_pats, method_chain_args, snippet, span_lint_and_then};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::snippet;
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::{iter_input_pats, method_chain_args};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
@@ -6,10 +9,11 @@
 use rustc_middle::ty::{self, Ty};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
+use rustc_span::sym;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for usage of `option.map(f)` where f is a function
-    /// or closure that returns the unit type.
+    /// or closure that returns the unit type `()`.
     ///
     /// **Why is this bad?** Readability, this can be written more clearly with
     /// an if let statement
@@ -51,7 +55,7 @@
 
 declare_clippy_lint! {
     /// **What it does:** Checks for usage of `result.map(f)` where f is a function
-    /// or closure that returns the unit type.
+    /// or closure that returns the unit type `()`.
     ///
     /// **Why is this bad?** Readability, this can be written more clearly with
     /// an if let statement
@@ -129,8 +133,8 @@ fn reduce_unit_expression<'a>(cx: &LateContext<'_>, expr: &'a hir::Expr<'_>) ->
             // Calls can't be reduced any more
             Some(expr.span)
         },
-        hir::ExprKind::Block(ref block, _) => {
-            match (&block.stmts[..], block.expr.as_ref()) {
+        hir::ExprKind::Block(block, _) => {
+            match (block.stmts, block.expr.as_ref()) {
                 (&[], Some(inner_expr)) => {
                     // If block only contains an expression,
                     // reduce `{ X }` to `X`
@@ -140,8 +144,8 @@ fn reduce_unit_expression<'a>(cx: &LateContext<'_>, expr: &'a hir::Expr<'_>) ->
                     // If block only contains statements,
                     // reduce `{ X; }` to `X` or `X;`
                     match inner_stmt.kind {
-                        hir::StmtKind::Local(ref local) => Some(local.span),
-                        hir::StmtKind::Expr(ref e) => Some(e.span),
+                        hir::StmtKind::Local(local) => Some(local.span),
+                        hir::StmtKind::Expr(e) => Some(e.span),
                         hir::StmtKind::Semi(..) => Some(inner_stmt.span),
                         hir::StmtKind::Item(..) => None,
                     }
@@ -164,17 +168,15 @@ fn unit_closure<'tcx>(
     cx: &LateContext<'tcx>,
     expr: &hir::Expr<'_>,
 ) -> Option<(&'tcx hir::Param<'tcx>, &'tcx hir::Expr<'tcx>)> {
-    if let hir::ExprKind::Closure(_, ref decl, inner_expr_id, _, _) = expr.kind {
+    if_chain! {
+        if let hir::ExprKind::Closure(_, decl, inner_expr_id, _, _) = expr.kind;
         let body = cx.tcx.hir().body(inner_expr_id);
         let body_expr = &body.value;
-
-        if_chain! {
-            if decl.inputs.len() == 1;
-            if is_unit_expression(cx, body_expr);
-            if let Some(binding) = iter_input_pats(&decl, body).next();
-            then {
-                return Some((binding, body_expr));
-            }
+        if decl.inputs.len() == 1;
+        if is_unit_expression(cx, body_expr);
+        if let Some(binding) = iter_input_pats(decl, body).next();
+        then {
+            return Some((binding, body_expr));
         }
     }
     None
@@ -197,7 +199,7 @@ fn let_binding_name(cx: &LateContext<'_>, var_arg: &hir::Expr<'_>) -> String {
 #[must_use]
 fn suggestion_msg(function_type: &str, map_type: &str) -> String {
     format!(
-        "called `map(f)` on an `{0}` value where `f` is a {1} that returns the unit type",
+        "called `map(f)` on an `{0}` value where `f` is a {1} that returns the unit type `()`",
         map_type, function_type
     )
 }
@@ -206,9 +208,9 @@ fn lint_map_unit_fn(cx: &LateContext<'_>, stmt: &hir::Stmt<'_>, expr: &hir::Expr
     let var_arg = &map_args[0];
 
     let (map_type, variant, lint) =
-        if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(var_arg), sym!(option_type)) {
+        if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(var_arg), sym::option_type) {
             ("Option", "Some", OPTION_MAP_UNIT_FN)
-        } else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(var_arg), sym!(result_type)) {
+        } else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(var_arg), sym::result_type) {
             ("Result", "Ok", RESULT_MAP_UNIT_FN)
         } else {
             return;
@@ -265,7 +267,7 @@ fn check_stmt(&mut self, cx: &LateContext<'_>, stmt: &hir::Stmt<'_>) {
             return;
         }
 
-        if let hir::StmtKind::Semi(ref expr) = stmt.kind {
+        if let hir::StmtKind::Semi(expr) = stmt.kind {
             if let Some(arglists) = method_chain_args(expr, &["map"]) {
                 lint_map_unit_fn(cx, stmt, expr, arglists[0]);
             }